diff options
| author | Oleg Nesterov <oleg@tv-sign.ru> | 2008-02-08 04:19:00 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-02-08 09:22:26 -0800 |
| commit | c0c0b649d67aa775aa9851de61aade17504be70c (patch) | |
| tree | 5902fb53a364155352fcc04e87860d724d8b31fd /kernel/ptrace.c | |
| parent | 34a1738f7da0b3d28d4b066d03a78f46b8cab68f (diff) | |
| download | lwn-c0c0b649d67aa775aa9851de61aade17504be70c.tar.gz lwn-c0c0b649d67aa775aa9851de61aade17504be70c.zip | |
ptrace_check_attach: remove unneeded ->signal != NULL check
It is not possible to see the PT_PTRACED task without ->signal/sighand under
tasklist_lock, release_task() does ptrace_unlink() first. If the task was
already released before, ptrace_attach() can't succeed and set PT_PTRACED.
Remove this check.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/ptrace.c')
| -rw-r--r-- | kernel/ptrace.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 2dc00298e678..fdb34e86f923 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -99,9 +99,12 @@ int ptrace_check_attach(struct task_struct *child, int kill) * be changed by us so it's not changing right after this. */ read_lock(&tasklist_lock); - if ((child->ptrace & PT_PTRACED) && child->parent == current && - child->signal != NULL) { + if ((child->ptrace & PT_PTRACED) && child->parent == current) { ret = 0; + /* + * child->sighand can't be NULL, release_task() + * does ptrace_unlink() before __exit_signal(). + */ spin_lock_irq(&child->sighand->siglock); if (task_is_stopped(child)) child->state = TASK_TRACED; |